Did a quick search, he has scored 16 out of 22 penalties (missing 6), which is a conversion rate of 73%. That needs drastic improvement, as Cal? said - but on the flip side, Barca has only not gone on to win in 1 of those matches.
CR7 though has taken 38 in his career, scoring 34, missing 4. With a conversion rate of around 90%. (at Madrid he's scored 23 out of 24).